Video compression and decompression are well known techniques for reducing either the bandwidth or the amount of memory needed to respectively carry or store video i.e., television-type signals. Video compression typically eliminates unnecessary information content from the signal. Well known methods of video compression include for instance color cell compression (CCC), joint photographics expert group (JPEG) compression and block truncation coding (BTC) compression. However, there is still a need for other compression methods especially those which address specific compression situations. For instance, it is frequently desirable in a computer system to store video information in a computer memory or disk drive. Since video information involves a large amount of data per video image or frame, compression is especially important in this context to reduce the required amount of memory. Many prior art compression methods require dedicated electronic circuitry, the need for which substantially increases the cost of video compression in conjunction with a personal computer system. Thus there is a need for video compression methods which provide compression additional over that of the prior art and which may be implemented in computer software only in conjunction with conventional personal computer hardware i.e., microprocessor, main memory, and disk drive.